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The dynamic response and damage fracture of brittle materials under explosive cutting have always been important research issues in the fields of military, aerospace, and other engineering fields. In this paper, a linear shaped charge cutting model for explosive cutting of brittle materials is proposed. This model suggests that explosive cutting is caused by the combined effects of jet penetration, spallation, and impact fracture. Theoretical calculation models for jet penetration, spallation, and impact fracture were constructed, and the concept of impact strength was introduced to establish dynamic mechanical performance parameters for brittle materials. A calculation program for explosive cutting of brittle materials was developed using the Python language, which can calculate the jet penetration depth, spallation thickness, and impact fracture thickness by inputting parameters such as the size and mechanical properties of the linear shaped charge and target plate, and determine whether the target plate can be successfully cut. Subsequently, a series of explosion cutting experiments and numerical simulations for brittle target plates were conducted to verify the accuracy of the calculation program. The results indicate a high degree of consistency between simulation, experimentation, and program calculation results. This work can provide guidance and promotion for the design and application of explosive energy harvesting cutters. [ABSTRACT FROM AUTHOR]

The best known solutions for k-message broadcast in dynamic networks of size n require Ω (nk) rounds. In this article, we see if these bounds can be improved by smoothed analysis. To do so, we study perhaps the most natural randomized algorithm for disseminating tokens in this setting: at every timestep, choose a token to broadcast randomly from the set of tokens you know. We show that with even a small amount of smoothing (i.e., one random edge added per round), this natural strategy solves k-message broadcast in \(\tilde{O}(n+k^3)\) rounds, with high probability, beating the best known bounds for \(k=o(\sqrt {n})\) and matching the Ω (n+k) lower bound for static networks for k=O(n1/3) (ignoring logarithmic factors). In fact, the main result we show is even stronger and more general: Given ℓ-smoothing (i.e., ℓ random edges added per round), this simple strategy terminates in \(O(kn^{2/3}\log ^{1/3}(n)\ell ^{-1/3})\) rounds. We then prove this analysis close to tight with an almost-matching lower bound. To better understand the impact of smoothing on information spreading, we next turn our attention to static networks, proving a tight bound of \(\tilde{O}(k\sqrt {n})\) rounds to solve k-message broadcast, which is better than what our strategy can achieve in the dynamic setting. This confirms the intuition that although smoothed analysis reduces the difficulties induced by changing graph structures, it does not eliminate them altogether. Finally, we apply tools developed to support our smoothed analysis to prove an optimal result for k-message broadcast in so-called well-mixed networks in the absence of smoothing. By comparing this result to an existing lower bound for well-mixed networks, we establish a formal separation between oblivious and strongly adaptive adversaries with respect to well-mixed token spreading, partially resolving an open question on the impact of adversary strength on the k-message broadcast problem. [ABSTRACT FROM AUTHOR]

This study examines how the strength of social ties between focal and peer fundraisers interacts with the network structure generated by these social ties to determine crowdfunding performance. With relationship intensity and preference similarity between focal and peer fundraisers as the two dimensions of tie strength, our study discloses how the benefits and costs associated with these tie strength dimensions are affected by network closure, the degree to which peer fundraisers are connected to each other. Our estimation results indicate that (1) relationship intensity and preference similarity exhibit inverted U-shaped relationships with crowdfunding performance, and (2) network closure attenuates the effectiveness of tie strength dimensions. Together, our study findings reveal an important interplay between indirect and direct social ties. In essence, social ties among peer fundraisers facilitate a group identity that reduces the returns of time and resources a fundraiser spends on strengthening ties with these peer fundraisers. [ABSTRACT FROM AUTHOR]

In order to enhance the flame retardancy of epoxy resin (EP) without affecting its mechanical properties, a phosphorus‐nitrogen synergistic flame retardant (MPCD) was synthesized in this paper by using melamine, paraformaldehyde, 9,10‐dihydro‐9‐oxa‐10‐phospha‐phenanthrene‐10‐oxide (DOPO) and cashew phenol as the raw materials, which was applied to the Ep in order to improve its flame retardancy and toughness. Experiments have shown that only 5% content of MPCD added into the EPs could achieve a significant LOI of 35.8% and successfully obtained a V‐0 rating in UL‐94 testing. In contrast, the PHRR with 5% additional MPCD was 456.4 kW/m2 and the THR was 80.2 MJ/m2, which were 52.6% and 29.4% lower than that of pure EPs, respectively. The PHRR of pure EPs was 963.1 kW/m2 and THR was 113.6 MJ/m2, which indicated that the addition of MPCD improved the EP system's flame retardant performance. The impact strength of pure EPs was 13.5 KJ/m2, and 5% addition of MPCD resulted in a 99% increase in the impact strength of EP/MPCD cured samples up to 26.9 KJ/m2, which was explained by the cashew phenol moiety's flexible chain segments. Furthermore, it is discovered by researching its flame‐retardant mechanism that the addition of MPCD may significantly improve the carbon layer's capacity to form char and maintain thermal stability. It can also efficiently trap free radicals and dilute the combustible gases produced during combustion. The flame retardant can increase the overall safety of the EP system by acting as a biphasic flame retardant in both the gas and the solidified phases at the same time. [ABSTRACT FROM AUTHOR]

The present study investigates the usability of lignocellulosic kapok fibers as a reinforcement for lightweight composites. Kapok fibers are modified by dewaxing followed by a silane coupling agent at different concentrations. The crystallographic structure and the alignment of silane linkage polymer chains on fiber structure are examined using X‐ray Diffraction (XRD). The linkage of chemical bonds (SiOC And SiOSi) between the polymer structure of the fiber and silane coupling agent is confirmed from FTIR spectroscopy. Additionally, the small angle X‐ray scattering (SAXS) study is done considering kapok fiber as a nonideal two‐phase system and the study investigates the modification occurring within the macromolecular structure of the kapok fiber. Following the grafting of silanes onto the fiber, silane‐modified kapok fiber‐reinforced epoxy composites are fabricated using the hand lay‐up technique. The chemical treatments on the fiber, enhanced flexural, tensile and impact strength of the composites by 132%, 102%, and 146% respectively. [ABSTRACT FROM AUTHOR]

Nucleating agents are crucial for modifying semi‐crystalline polymers, but the impact of different end‐group structures on crystallization behavior remains unclear. This study synthesized succinic dihydrazide nucleating agents with various end groups (methyl, ethyl, and tert‐butyl) for PET composite materials. The tert‐butyl‐terminated nucleating agent showed the best performance, increasing the crystallization peak temperature to 203.8°C, crystallinity to 27.3%, and reducing half‐crystallization time to 2.8 min at 220°C. It also enhanced the impact strength to 47.2 kJ·m−2 and flexural modulus to 2623 MPa, while improving Vicat softening temperature and heat distortion temperature by 41 and 8°C, respectively. The results from FTIR and Raman Spectroscopy indicate that the interactions between the end groups of the nucleating agent and the CH bonds in the PET structure, the π–π interactions between the nucleating agent and the PET molecular structure, as well as the modulation of the PET chain conformation by the nucleating agent, are the primary factors contributing to the enhanced crystallinity of PET. This study provides a new approach for designing efficient nucleating agents for high‐performance materials. [ABSTRACT FROM AUTHOR]

Incorporating recycled plastics into the manufacturing process is an essential way to establish a sustainable plastics economy. However, current processes are limited by the degradation of mechanical properties, high cost, and inconsistent product quality compared with their virgin counterparts. Here, we present an upcycling strategy for waste plastics where waste acrylonitrile‐butadiene‐styrene (reABS) is first grafted with maleic anhydride (MAH), then utilized to compatibilize nylon 6(PA6)/ABS and PA6/ABS/CaCO3 blends. The reABS‐g‐MAH exhibits improved Young's modulus and tensile strength, but lower strain at break and impact strength compared with reABS. As an additive, reABS‐g‐MAH effectively compatibilizes PA6/ABS and PA6/ABS/CaCO3 blends, indicated by greatly decreased PA6 domain size, homogeneous dispersion of fillers, and narrowed glass transition temperature regions between PA6 and ABS. Adding only 5 wt% reABS‐g‐MAH increases the Young's modulus, strain at break, and impact strength of PA6/ABS blends by 26%, 180%, and 110%, respectively, compared with uncompatibilized samples. Similarly, for PA6/ABS/CaCO3 blends, the strain at break and impact strength increase by 370% and 150%, respectively, while the Young's modulus and tensile strength show increases of 5% and 10%. The results show that this strategy of using polar groups to functionalize waste plastics as compatibilizers may open numerous opportunities for upcycling waste plastics. [ABSTRACT FROM AUTHOR]

This study examined the flexural and impact responses of sandwich panels with honeycomb core and hybrid fiber-reinforced composite skins. The influence of laminate composition and thickness on these mechanical properties was investigated. Carbon, glass, and Kevlar fibers were employed in various combinations to fabricate the composite skins. The findings revealed a general trend of increasing flexural strength, modulus, and toughness with rising laminate thickness. However, the laminate configuration exerted a significant influence. Configurations with a higher carbon fiber content exhibited superior strength but reduced strain (ductility). Conversely, configurations incorporating glass or Kevlar fibers demonstrated enhanced ductility at the expense of strength. Overall, configurations utilizing dry carbon fabric skins achieved the highest flexural strength and toughness, while the combination of carbon and glass fibers offered a desirable compromise between strength and ductility. Regarding impact resistance, configurations with solely carbon fibers initially showed the best performance. However, configurations employing a combination of carbon and glass fibers exhibited a noteworthy increase in impact strength with increasing laminate thickness. This observation suggests that the inclusion of glass fibers alongside carbon fibers provides a well-balanced combination of strength and energy absorption capability. [ABSTRACT FROM AUTHOR]

The primary objective of this study is to determine how the presence of nano-particles such as titanium dioxide and silicon dioxide (TiO2 and SiO2), as well as fiber alignment, affects the flexural and impact strength of the jute/kenaf nano-composite. The study investigates the independent variables of nano-particle weight percentages (TiO2 and SiO2) and fiber angle orientation to understand their combined impact on the flexural and impact strength of hybrid composites. Twenty experiment runs were performed using a response surface methodology (RSM) with a central composite design (CCD), a center point with six replicates, and altering the specified parameters. Statistical analysis of the outcomes highlights the significant influence of the chosen variables on both flexural strength and impact resistance properties. Flexural strength varied from 98 to 137 MPa throughout design levels, and impact strength varied from 282 to 328 kJ/m2 throughout design levels. The maximum flexural strength, 137 MPa, was attained at 2.5 wt% TiO2, 2.5 wt% SiO2, and an 80° fiber angle orientation, while the foremost impact strength attained, 328 kJ/m2, was obtained at 1 wt% TiO2, 2.5 wt% SiO2, and an 80° fiber angle orientation. This study found that the composite material tested is acceptable for replacing automobile interiors, particularly car dashboards, meeting current automotive industry specifications. [ABSTRACT FROM AUTHOR]

Although considerable research has explored the static and seismic bearing capacity of strip footings on slopes or excavations, the influence of clay strength anisotropy on the bearing capacity of strip footing near excavations, specifically considering pseudo‐dynamic conditions, remains unexplored. This study used the finite element limit analysis (FELA) method to evaluate the impact of clay strength anisotropy on the seismic bearing capacity of strip footings. The effects of various dimensionless parameters on the bearing capacity were examined, which include shear wavelength, the setback distance ratio, vertical height ratio, soil strength ratio, soil strength heterogeneity, anisotropic ratio, and horizontal and vertical acceleration coefficients. Design charts were developed to compute the seismic bearing capacity of strip footings on nonhomogeneous and anisotropic excavations under pseudo‐static conditions. Furthermore, the effects of vertical acceleration coefficients and shear wavelength on the seismic bearing capacity of strip footing near excavation in nonhomogeneous and anisotropic soils were investigated. [ABSTRACT FROM AUTHOR]

This study uses a rotomolding procedure to produce hollow cubes made of linear low-density polyethylene (LLDPE) and coconut fibers (CF). The purpose is to investigate the effect of different CF content (0, 5, 12.5, and 20 wt%) and size (100 and 50 mesh) on composite properties. As the CF content rises, the density of all composites decreases due to an increase in material porosity, a result of poor adhesion between the fiber and LLDPE. Impact strength reduced as the content of CF increased, except for the composite with 5 wt% of CF and 50 mesh size. The ineffective adhesion between coir fibers and LLDPE, along with the presence of voids in the matrix, caused the mechanical properties to deteriorate as the CF content increased. The flammability test revealed that all samples dripped. The neat LLDPE sample deformed, whereas the LLDPE/CF composites maintained their shape. This behavior suggests that CF plays a structural role in burning composites. Maleic anhydride-grafted polyethylene (MAPE), calcium stearate, and magnesium stearate additives did not contribute to reducing the composite’s porosity. MAPE was the only additive that did not reduce the elastic modulus of composites. [ABSTRACT FROM AUTHOR]

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Expanded polystyrene (EPS) waste also known as Styrofoam is a common material found in packaging and insulation applications and presents significant environmental challenges due to its nonbiodegradable nature. To address this issue, researchers have explored EPS waste as a potential polymer matrix for developing composite materials. Many researchers have studied the physical, mechanical, and thermal behavior of EPS‐based materials. Therefore, this review provides the current state of knowledge regarding the physical, thermal, and mechanical properties of EPS‐based composites. The effect of reinforcement content, filler size, EPS content, processing method, and other factors that affect the properties of EPS‐based composites is covered in this review. The physical properties examined include density, porosity, and water absorption properties, while the mechanical behavior encompasses tensile strength, impact strength, and flexural resistance of EPS waste–based materials. This review also identifies key findings from various studies and discusses the influence of EPS waste on the overall performance of the composites. Moreover, it highlights the challenges and opportunities associated with utilizing EPS waste in composite materials, along with potential avenues for future research. Overall, this review serves as a valuable resource for researchers, engineers, and stakeholders interested in understanding the physical, thermal, and mechanical properties of EPS waste–based composites and their potential applications in sustainable material development, thereby enhancing the commercial value of recycled materials. [ABSTRACT FROM AUTHOR]

Duplex stainless steels provide a desirable combination of corrosion resistance, strength and toughness. Additive manufacturing of duplex stainless steels can be challenging due to high cooling rates and repeated reheating, which can produce detrimental microstructural constituents. In this study, a coaxial directed energy deposition system with laser and wire was used to deposit 2205, 2209 and 2509 duplex stainless steels. Corrosion resistance, strength and impact toughness in both as-built and solution annealed condition was tested and the microstructure was characterized. Solution annealing improved impact toughness considerably, produced a slight increase in corrosion resistance and a slight decrease in tensile strength. The 2205 material surpassed all common requirements and exhibited better corrosion resistance than 2209 due to less segregation between austenite and ferrite. Segregation of alloying elements was lower in intragranular austenite than grain boundary allotriomorph and Widmanstätten austenite. The 2209 and 2509 materials provided relatively low strength, especially in the solution annealed condition. For the 2509 material, sigma phase caused low as-built corrosion resistance and impact toughness. Overmatching welding consumables were found to be less suitable as feedstock for additive manufacturing due to high austenite content in the deposited material and lower corrosion resistance than conventional duplex compositions. [ABSTRACT FROM AUTHOR]

Highlights Typical space domestic waste (SWL‐10%, SWL‐25%, SWL‐40%, SWL‐50%) added with different proportions of linear low density polyethylene (LLDPE) was used as raw material to prepare high‐stability composite materials by heating and compression molding. The hot pressing of LLDPE and space waste not only effectively reduces volume, but also yields composite material with superior physical and mechanical properties. This study investigated the impact of hot pressing process on the stability of composites prepared from multiphase space domestic waste. The physical and mechanical properties of these compressed blocks were analyzed, while scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were employed to characterize the composites' properties. Our results demonstrate that BSWL‐40% (hot pressing temperature (160 °C), LLDPE addition ratio (50%)) composite achieves a volume reduction rate as high as 96%, with an initial density increase by 16.1%. Furthermore, the compressive strength and impact strength of BSWL‐50% composites increased by 19% (6.85 MPa) and 71% (14.3 KJ/m2). These improvements can be attributed to enhanced physical/mechanical interlocking structure at a temperature of 160 °C based on SEM analysis findings. Fourier transmission infrared spectroscopy also confirmed the presence of ester bonds between LLDPE and space domestic waste materials. Solid‐plastic composites were successfully prepared by hot pressing. LLDPE particles were added to domestic waste for composite fabrication. The BSWL‐40% composite achieved a high volume reduction of 96%. The stability of the composite was judged by physical and mechanical properties. The BSWL‐50% composite exhibited superior mechanical properties. [ABSTRACT FROM AUTHOR]

To address the challenges of performing in-situ tests on riverbed overburden gravel, this study employs three scaling methods—equal mass substitution, similar gradation, and the mixed method—to investigate the original gradation of the gravel. Large-scale triaxial consolidated drained shear tests were conducted to evaluate the effects of the maximum particle size reduction ratio (M) and confining pressure on the stress–strain behavior, fractal dimension, particle breakage, and the parameters of the Duncan-Chang model (an elastic model describing nonlinear stress-strain relationships). The study explores how scaling, based on fractal dimension and particle breakage rate, impacts the strength and deformation characteristics of gravel materials. The results show that increasing confining pressure typically leads to higher material strength. As confining pressure increases, particle breakage becomes more pronounced across the various scaling methods. Gravel processed using the similar gradation method exhibited the highest strength, the smallest change in fractal dimension, and the lowest breakage rate, followed by the mixed method. Furthermore, as the M value increases, peak stress also rises, with the modulus coefficient (k) and bulk modulus coefficient (Kb) in the Duncan-Chang model increasing by 4.5 times and 3.3 times, respectively, for M = 15 compared to M = 0. A clear relationship was observed between the change in fractal dimension before and after testing and the breakage index (Bg). As the M value increases, both the difference in fractal dimension and the breakage rate decrease, suggesting that larger M values lead to reduced particle breakage and improved mechanical stability. [ABSTRACT FROM AUTHOR]

In this paper, a photosensitive resin was successfully synthesized using epoxy as a matrix and the effect of nanosilica on its properties was investigated. Micromorphology analyses show that the nanosilica has good dispersion and strong interaction with the matrix. Additionally, a finite element model was developed to predict the tensile performance of the nanocomposite under high-strain loads. Molecular dynamics simulations demonstrated a favorable binding energy between nanosilica and epoxy resin. The effects of nanosilica on the fracture toughness and energy release rate of photosensitive resins were investigated using load-enhanced tensile test method. The results showed that the addition of 1.0 wt.% nanosilica particles increased the toughness of the resin from 0.45 MPa m1/2 to 0.79 MPa m1/2, and the energy release rate from 248.3 J/m2 to 555.7 J/m2; compared with the neat photosensitive resins, the incorporation of nanosilica increased the tensile and impact strengths of the resins by 26.8% and 49.2%, respectively. The nanosilica was used to improve the tensile strength and impact strength of the resin by 26.8% and 49.2% respectively compared with the neat photosensitive resin. Electrochemical corrosion analysis showed that the photosensitive resin/nanosilica composites have excellent corrosion resistance. Under different corrosion environments of acid, alkali, and salt, the addition of 1 wt.% nanosilica in the photosensitive resin composite led to an increase in corrosion voltage by 0.023 V, 0.004 V, and 0.1 V respectively compared to neat photosensitive resin. Additionally, the corrosion current density decreased by 1.39 × 10−6 A/cm2, 0.525 × 10−4 A/cm2, and 2.57 × 10−6 A/cm2, respectively. On this basis, the independently synthesised photosensitive resin has excellent strength and 0.01 mm printing accuracy. [ABSTRACT FROM AUTHOR]

The wear-resistant coating on the hull surface can be peeled off under the collision between the ice during the navigation of polar ships. In this study, the damage and peeling of the anti-icing wear-resistant coating at different impact angles, impact speeds, and temperatures were simulated. The static icing adhesion shear strength and normal peel strength of the anti-ice wear-resistant coating were examined, and the coating peeling criterion with temperature term was proposed. Furthermore, the damage and peeling of the anti-ice wear-resistant coating at different impact angles, impact speeds, and temperatures were simulated numerically. [ABSTRACT FROM AUTHOR]

Carbonaceous shale is a dark, soft rock with poor water stability. To evaluate the feasibility of using this rock as a filler material for highway embankments, the scanning electron microscopy (SEM) test, the particle size analysis before and after vibration compaction, the California bearing ratio (CBR) test of repeated dry–wet alternation, the compression tests with different moisture, and the resilience modulus test of in‐site infiltration were conducted. The test results indicated that the higher weathering degree of carbonaceous shale usually goes with the looser structure and the higher content of hydrophilic clay. The larger particle size in the filler has a higher crushing ratio. The CBR value of the filler exhibited a rapid decay and then gradually stabilized with the increase of the time of dry–wet alternation. The compression deformation and particle breakage ratio of the filler material with saturated water content significantly increased compared to the optimal water content. After being infiltrated by water, the resilience modulus of the top surface of the carbonaceous shale filler decreased significantly. According to the research, although moisture content changes and dry–wet alternation have a significant impact on the strength and deformation performance of carbonaceous shale, it can be used as embankment filling material under the premise of taking engineering measures such as setting waterproof layers, restricting usage positions, and eliminating disintegration in advance. The research results can guide the design and construction of embankments using carbonaceous shale as filling material. [ABSTRACT FROM AUTHOR]

Highlights The present work investigates effect of the incorporation of GNPs into epoxy matrix composites reinforced with CFs on their electrical, mechanical and viscoelastic properties. The GNP content in the composite were added as 0.1%, 0.2%, 0.3%, and 0.4% by weight. The study presents detailed analysis of conductivity mechanism revealing an 8‐fold increase in surface electrical conductivity at 0.4 wt% GNP content, reaching 2.32 S/m. The mechanical properties showed significant enhancement with the incorporation of GNPs up to 0.3 wt%, reaching a maximum tensile strength of 1008 MPa and peak flexural strength of 952 MPa, and the highest impact strength of 13 J/cm2. However, a decline in mechanical performance was observed at 0.4 wt% GNP content, primarily due to fiber‐matrix debonding. The DMA analysis further revealed an increase in the storage modulus and loss modulus at 0.1 wt% GNP content, reaching 10,099 and 1570 MPa, respectively. However, at higher GNP content, adverse effects on the composite's behavior were observed, attributed to uneven distribution and interactions of the GNPs. Impact of GNPs on the electrical and viscoelastic properties of CFRP analyzed. GNPs enhance surface electrical conductivity of CFRP composites at 0.4 wt%. GNPs improve viscoelastic properties of CFRP composites at 0.1 wt%. Suitable mechanisms illustrated, correlated with results and discussed. [ABSTRACT FROM AUTHOR]

Highlights Polypropylene‐reinforced composites mostly exhibit a trade‐off between stiffness and toughness. In this study, the impact of incorporating polyolefin elastomer (POE) and Polyvinyl Alcohol (PVA) fibers as individual and hybrid reinforcement to glass fiber‐reinforced polypropylene composite in the presence of a compatibilizer was explored. The main focus was on achieving an optimal stiffness/toughness balance. Several ternary and quaternary hybrid composite systems were developed and analyzed. All components were melt‐blended using a twin‐screw extruder and then injection molded for subsequent mechanical and morphological analysis. A significant stiffness of approximately 2.4 GPa Young's modulus, and notched izod impact strength ranges between 250 and 400 J/m can be attained with the quaternary hybrid system, PP/GF/POE/PVA fibers. Its performance can be controlled by altering the POE/PVA fibers ratio to achieve the targeted stiffness/toughness balance. These values represent a remarkable increase, with Young's modulus being 120% higher and the izod impact strength surpassing that of the control sample by over 800%. The achieved results aligned with the requirements of the automotive industry, so the developed composites could have a high potential for automotive parts. Ternary and quaternary hybrid systems were fabricated by a twin‐screw extruder. An improvement of 120% in stiffness and 800% in toughness was observed. Distinct micromechanical deformation mechanisms were identified. Remarkable stiffness‐toughness balance was achieved. Reduction in weight makes the system suitable for automotive applications. [ABSTRACT FROM AUTHOR]

Highlights Basalt fiber (BF)‐reinforced thermoplastic composites are not only made with little environmental pollution and recyclable, with obvious environmental value, but also have excellent mechanical properties, excellent resistance to high temperature and corrosion. In the present study, modifications to the interface of BF were performed using monoaminosilane and diaminosilane agents, specifically 3‐aminopropyltrimethoxysilane (SATMS) and N‐(2‐aminoethyl)‐3‐aminopropyltrimethoxysilane (DATMS), along with a urea‐modified silane, 3‐urethylpropyltrimethoxysilane (SUTMS). These modifications were evaluated against one another. Utilizing a film lamination technique, composites of BF and thermoplastic polypropylene resin (BF‐PP) were fabricated. Analytical assessments included examining the modified fibers' surface morphology, chemical structure, and roughness. Mechanical assessments of the modified BF‐PP composites were conducted, revealing that composites treated with the urea‐inclusive silane agent (BF/SUTMS‐PP) exhibited superior performance, enhancing flexural strength by 26%, tensile strength by 22.4%, and notched Izod impact strength by 21%. However, because of the lower thermal stability of SUTMS, when the processing temperature exceeds 240°C, there is a decomposition of the heated Y‐base end, thus affecting the mechanical properties of BF/SUTMS‐PP. The basalt fibers were modified by SATMS, DATMS, and SUTMS. The urea‐containing silane coupling agent has the strongest enhancement effect. Composite reinforced with SUTMS‐BF displayed the best mechanical properties. [ABSTRACT FROM AUTHOR]

Flax fiber has emerged as a promising, eco‐friendly alternative to traditional synthetic reinforcement in polymer composites. However, manufacturing biocomposites using three‐dimensional (3D) printing technology is typically accompanied by significant processing challenges and weak product performance under dynamic loading conditions. This study aims to unlock the potential of 3D‐printed polylactic acid (PLA) by incorporating chemically modified chopped flax fibers and thermoplastic polyurethane elastomer to improve impact strength and processability. To achieve this, we employed the fused deposition modeling (FDM) technique to prepare composite specimens for the study. The crystallization behavior, tensile and impact properties, as well as the fracture behavior of the composites were investigated. The findings suggest that our approach stands out because it not only facilitates the challenging task of 3D printing PLA with fiber additives of high weight fraction and high aspect ratio but also results in a remarkable 120% enhancement in impact strength and an around 31.2% increase in tensile elongation compared to neat PLA, without compromising the elastic modulus. Highlights: Flax fibers were modified through alkalization and silanization.Alkalization significantly enhanced printing quality.Silanization reduced fiber attrition and doubled the fiber aspect ratio.TPU particles facilitated the 3D printing of biocomposites.For the first time, the hybrid strategy doubled the impact strength of PLA. [ABSTRACT FROM AUTHOR]

Additive manufacturing has enhanced the production of complex parts with greater efficiency. However, inherent drawbacks such as reduced mechanical properties still pose challenges, necessitating further improvements to bridge the gap and meet industry demands. Therefore, this study investigated the use of glass fiber woven fabric with vat‐photopolymerization printing to achieve composite parts with superior mechanical properties. This approach offered an advantage in reducing the production time required for fiber‐reinforced composites by eliminating the need for curing processes or vacuum infusion. The mechanical properties of the composite panels manufactured with this method were investigated using flexural, interlaminar shear (ILSS), impact tests with different fiber orientations, and fiber volume fractions. The results of the mechanical tests showed maximum flexural strength of 295 MPa, impact strength of 174 kJ/m2, and ILSS of 20.58 MPa. In addition, optical images were taken to examine the cross‐section of the printed parts, which revealed a uniform and good wetting of the fibers. The findings suggest that glass fiber woven fabric in vat printing is a promising approach for producing composite parts with enhanced mechanical properties and reduced production rate. Highlights: Additive manufacturing of glass fiber woven fabric reinforced with VPP printing.Reduced production time and microstructure by using layer‐by‐layer manufacturing.Maximum flexural strength: 295 MPa, impact strength: 174 kJ/m2, ILSS: 20.58 MPa.Consistent porosity values with the increasing number of layers.Promising for producing standard and thick composites with improved properties. [ABSTRACT FROM AUTHOR]

Interfacial adhesion properties are a key factor affecting the mechanical properties of composites. It is a very effective way to improve the low‐velocity impact resistance of composites by improving the interfacial adhesion properties. To improve the fiber/matrix interfacial adhesion properties of GF/PA6 (glass‐fiber/polyamide 6) composites, polyethyleneimine (PEI) and γ‐aminopropyltriethoxysilane (KH550) were used to co‐modify GF together in this study. The GF/PA6 composites with different modifications of glass‐fiber (GF) were also prepared using a hot pressing process, and then their flexural strength, shear strength, pendulum impact strength, and low‐speed impact resistance were investigated. Next, the relationship between fiber/matrix interfacial adhesion and mechanical properties of GF/PA6 composites was investigated by combining x‐ray photoelectron spectroscopy, scanning electron microscopy, and x‐ray computed tomography test results. The results showed that the GF‐reinforced PA6 matrix composite with co‐modified GF by PEI and KH550 (PEI‐KH550‐GF/PA6) had the best mechanical properties, with flexural, shear, and pendulum impact strengths of 660.7 MPa, 53.1 MPa, and 261.6 kJ/m2, respectively. Furthermore, the low‐velocity impact resistance was measured in terms of stress peak, absorbed energy, residual stress, and damage extension, and the results showed that the low‐speed impact resistance of PEI‐KH550‐GF/PA6 composites was also substantially improved that the Fmax increased from 7402.1 to 10414.0 N. Highlights: Due to the poor surface activity of GF, in this experiment, GF was co‐modified with PEI and KH550 to achieve better fiber/matrix interfacial adhesion and successfully improve the mechanical properties of the composites;Different modification methods are used to improve the interfacial adhesion of the fiber/matrix interface. The relationship between the interface and impact strength of composites has been studied;The relationship between fiber/matrix interfacial adhesion and internal cracking in composites was investigated using X‐CT and SEM and other test results. [ABSTRACT FROM AUTHOR]

Highly transparent and mechanically robust thermoplastic composites have been developed by hot‐pressing PETG with E‐glass fabrics. The tow‐spreading technique facilitates the reduction of internal defects and fiber crimp angle in the composites, thereby significantly improving their optical and mechanical properties. The optimized composite containing 55.1 vol% glass fibers and 0.4 mm thickness has a high transmittance of 86.1%@616 nm and a low overall haze of 7.2%. Moreover, the 1 mm thick composites exhibit tensile strength of up to 340 MPa and impact strength of up to 86.3 kJ/m2. After 28 days of hygrothermal or UV aging, the composites show minimal changes in their glass transition temperature and thermal degradation temperature. The chemical structure also remains unchanged, with no observed crystallization. In comparison to UV aging, the composites demonstrate better resistance against hygrothermal aging. Specifically, the hygrothermal aged sample displayed a light transmittance retention rate of 93.5% and a bending strength retention rate of 94.3%, while these values were reduced to 73.3% and 90.5%, respectively, in the UV aged sample. The opto‐mechanical properties enhanced mechanism and aging degradation mechanism have been identified by microscopic morphological observation. This work provides an innovative and straightforward approach to fabricate transparent, recyclable, high‐strength thermoplastic composites. Highlights: Highly transparent, mechanically robust, recyclable glass‐fabric reinforced thermoplastic composites are fabricated.Composites with spread‐tow fabrics exhibits improved transparency.The fabrication route is scalable and cost‐effective.The mechanism for opto‐mechanical properties enhancement are proposed. [ABSTRACT FROM AUTHOR]

Continuous fiber reinforced Nylon‐6 composites with high strength have been widely used in automotive, wind turbine blades, aerospace, and military fields. Here, we present a synergistically reinforced strategy to enhance the mechanical properties of the continuous glass‐fiber reinforced Nylon‐6 (CGF/PA6) and basalt‐fiber reinforced Nylon‐6 (CBF/PA6) composites via in‐situ polymerization, simultaneously employing thermoplastic polyurethane (TPU) and modified calcium carbonate (M‐CaCO3) as the toughening and strengthening materials. The micro‐morphology, mechanical properties, thermostability, water absorption, and flowability of composites are investigated. Significantly, the synergistic effect of TPU and M‐CaCO3 can improve mechanical properties, thermal stability (335.6 and 396.5°C in the T50%), and flowability (43.02 and 40.56 g/10 min) of the modified continuous glass‐fiber reinforced Nylon‐6 (M‐CGF/PA6) and basalt‐fiber reinforced Nylon‐6 (M‐CBF/PA6) composites, especially the high tensile strength (96.07 and 217.43 MPa) and impact strength (95.03 and 206.36 kJ/m2) which increases by 8.53% and 5.18% for the tensile strength and 91.25% and 100.27% for impact strength compared with the unmodified CGF/PA6 composites and CBF/PA6 composites. This work provides theoretical support for continuous fiber reinforced Nylon‐6 composites. Highlights: Continuous fiber reinforced Nylon‐6 Composites is prepared by in situ polymerization.In situ polymerization is beneficial to the good impregnation of continuous fibers and uniform dispersion of modified calcium carbonate (M‐CaCO3).The modified continuous fiber can improve the interfacial bonding properties of composites.The TPU and M‐CaCO3 synergistically reinforce the mechanical properties of composites.The M‐CaCO3 nanoparticles are uniformly dispersed in the composites. [ABSTRACT FROM AUTHOR]

Parts made from carbon fiber reinforced polyetherketoneketone (CF/PEKK) primarily use mechanical connections during assembly, where the quality of hole processing directly impacts the connection strength. However, defects like delamination, burrs, and fiber pull‐out frequently occur during drilling. While existing research focuses on optimizing conventional drilling (CD) and helical milling (HM), ultrasonic vibration‐assisted drilling (UVAD) shows superior performance in reducing thrust force and defects. This study experimentally evaluates the hole‐making performance of CF/PEKK using the UVAD method. It examines the effects of ultrasonic vibration on thrust force, drilling temperature, processing damage, chip morphology, and surface microstructure, and discusses the damage suppression mechanism. The results show that the UVAD method significantly reduces thrust force and drilling temperature compared to the CD method, with similar trends in delamination and burr damage. This study demonstrates that using the UVAD method for drilling CF/PEKK laminates effectively reduces thrust force, drilling temperature, and machining damage, thereby significantly improving processing quality. The material removal mechanism of UVAD was analyzed, offering substantial insights and practical guidance for the efficient drilling of CF/PEKK laminates. Highlights: The drilling performance of CF/PEKK was studied.The drilling quality of UVAD and CD is compared by experiments.UVAD has a lower thrust force and drilling temperature.UVAD can reduce machining damage and improve machining quality. [ABSTRACT FROM AUTHOR]

In this work, the foam SiC ceramics were prepared by conventional and microwave sintering methods at 800 °C combined with organic template impregnation method. The microstructure, crystal structure, and mechanical properties of the samples were evaluated. Compared with conventional sintering, microwave sintering has obvious advantages such as more uniform element distribution, shorter sintering time, and better mechanical properties. Its bending strength and impact resistance reach 2.28 MPa and 4.9 kJ/m2, respectively. The dielectric constant and reflection loss of the samples were tested, and the samples sintered by microwave between room temperature and 500 °C showed better dielectric properties; as well as better microwave absorption performance at frequencies of 2–18 GHz. The mechanism of microwave sintering has been elucidated, and the heating method of microwave from inside to outside is an important reason for the excellent mechanical and absorbing properties of materials. [ABSTRACT FROM AUTHOR]

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The aim of this study was to evaluate the mechanical properties and degree of conversion of a novel 3D-printing model resin and compare it to eight commercially available model resins. An experimental resin formulated by our proprietary resin technology along with DentaModel, NextDent 2, KeyModel Ultra, Rodin Model, Die and Model 2, DMR III, LCD Grey, and Grey Resin were used in this study. Parallelepiped specimens (2 × 2 × 25 mm, n = 5) were printed and measured for their flexural strength (FS), flexural modulus (FM), and modulus of resilience (MR) in accordance with ISO-4049. Dumbbell-shaped specimens (Type V, n = 5) were printed to test tensile strength (TS) and elongation according to ASTM-D638. Barcol hardness (BH) was measured based on ASTM D2583 using broken tensile strength specimens. Izod-type test specimens (3.2 × 12.7 × 63.5 mm, n = 10) were printed, notched, and determined for impact strength according to ASTM D256-10. The degree of conversion was measured using FTIR (n = 5). Data were analyzed using one-way ANOVA and post hoc Tukey tests (p ≤ 0.05). The experimental resin exhibited a similar or significantly greater flexural strength (88.8 MPa), modulus of resilience (2.13 MPa), tensile strength (54.4 MPa), and hardness (82.9) than most model resins (FS 62.6–90.1 MPa, MR 1.37–2.0 MPa, TS 36.3–54.6 MPa, BH 66.1–83.7). The elongation (6.2%) and impact strength (14.2 J/m) of the experimental resin are statistically the same as those of most resins (3.0–7.5%, 13.8–16.4 J/m). However, the experimental resin has a significantly lower flexural modulus (1.97 GPa) than most resins (2.18–3.03 GPa). The experimental resin exhibited a significantly higher degree of conversion (66.58%) than most resins (1.11–62.34%) for 40 s of light curing; however, a similar or higher value (84.87%) than most resins (72.27–82.51%) was obtained for 3D-printed objects. The newly formulated 3D-printing model resin exhibited adequate mechanical properties and degree of conversion, which is comparable to the commercially available 3D-printing model resin materials. The new 3D-printing model resin can be used for modeling applications in restoration, orthodontics, implants, and other cases. [ABSTRACT FROM AUTHOR]

This study investigates the microstructural characterization of cellulose nanocrystals (CNC) and microcellulose (MC) extracted from bamboo fibers (Bambusa longispatha) and their potential as reinforcement agents in ordinary Portland cement (OPC) composites. CNC with a mean particle size of 29.3 nm and MC with a mean size of 14.6 × 103 nm were incorporated into OPC at varying concentrations (0.1%, 0.2%, 0.4%, and 0.6% by cement mass). The compressive strength analysis revealed that increasing MC content led to a decrease in strength, with reductions ranging from 8.8% to 25.9% relative to the control OPC, while the CNC-enhanced composite at 0.4% achieved the highest compressive strength of 43.2 MPa. Flexural strength analysis indicated a minor increase in strength with MC addition (from 7.5 MPa to 8.1 MPa), while CNC addition at 0.1% improved flexural strength to 8.2 MPa but declined with higher concentrations. SEM and stereo microscopy demonstrated MC and CNC dispersion and highlighted microstructural differences, including pore distribution in the composites. XRD analysis showed increased crystallinity for CNC composites compared to pure OPC, with the highest crystallinity index of 52.2% observed at 0.4% CNC. This study highlights that CNC at specific concentrations can enhance OPC mechanical properties, while higher MC and CNC additions may impact strength properties variably due to their microstructural integration and crystallinity. These findings support the potential for bamboo-derived cellulose materials in enhancing cementitious composite performance. [ABSTRACT FROM AUTHOR]

From both economic and environmental points of view, the reuse of dredged sediments in the direct onsite casting of concrete represents a promising method for replacing sand. The aim of this study was to develop a cementitious material that (i) reuses the thin particles of sediments; (ii) has a low density due to the incorporation of air foam in the material; and (iii) achieves a minimum mechanical strength of 0.5 MPa for embankment applications. This study focused on the characterization of a non-standard "concrete", which is a mixture of a synthetic soil (80% montmorillonite and 20% calibrated sand) and cement. To reduce its density, air foam was incorporated into the material during the manufacturing process (air-foamed lightweight clay concrete—AFLCC). The study results highlight that a density around 1.2 (unit: g/cm3/1 g/cm3) can be obtained. This density reduction can be obtained with a certain degree of workability when the material is in a fresh state. To obtain this workability, a certain amount of water must be added; however, the addition of water has a significant impact on the compressive strength of the AFLCC. As such, a mathematical equation correlating the compressive strength, the density, and the percentage of cement is proposed in this study. The mechanical strength results of the AFLCC at different times, in conjunction with the Vicat results, show that the porosity created by the air foam has the effect of slowing down the hydration mechanism of the cement. The porosities obtained are consistent with the density results. The characteristic radii indicate large pore sizes for formulations with low fluidity in the fresh state when air bubbles are incorporated. [ABSTRACT FROM AUTHOR]

The influence of the addition of ground buckwheat hulls on the properties of biocomposite on the basis of 3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) is presented here. The changes in the material after repeated reprocessing—up to five recycling cycles—are written in the paper. Analysis of the shrinkage, water adsorption, selected mechanical properties, tensile impact strength, hardness and the microstructure of the surface layer was performed. The results show that the application of the buckwheat hulls into the biopolymer decreases the material shrinkage. It improves the material dimensional stability, as well as increases the water adsorption in the wake of the hydrophobic properties of the filler. The addition of the natural filler also leads to an increase in composite stiffness. The decrease in the tensile impact strength and the elongation at break is also noted. The reprocessing of the biocomposite initially led to a decrease in its mechanical properties, but the results stabilized after further processing cycles. This indicates the improvement of the microstructure homogeneity. The microscopic analysis shows that buckwheat hull particles were better embedded in the matrix after recycling. The increase in hardness was also noted. The PHBV–ground buckwheat hull biocomposite is characterized by stable mechanical properties and by recycling resistance, which makes it a promising material in terms of the sustainable development. [ABSTRACT FROM AUTHOR]

Highlights In this study, a series of sustainable eco‐friendly epoxy resin (EP)‐based biomass composites (DSA‐CS/EP) were prepared using bisphenol A EP as matrix, 2‐methylimidazole as curing agent, and corn stalk (CS) esterified with dodecene succinic anhydride (DSA) as filler. The static contact angle test results showed that the hydrophobicity of CS after esterification with DSA (DSA‐CS) was enhanced, which results in the compatibility of DSA‐CS with EP matrix was improved. And then, the DSA‐CSs were dispersed homogeneously in the matrix without agglomerating. The morphology and properties of the biomass composites were studied and analyzed in order to elucidate the toughening mechanism of CS and DSA‐CS. When the content of DSA‐CS is 15 wt%, the tensile strength and impact strength of DSA‐CS/EP reached a maximum value of 30.39 MPa and 3.34 KJ/m2, which were increased by 128.49% and 81.52% compared with pure EP. Finally, it is deduced that the possible toughening mechanism is that DSA‐CS can not only share part of the external stress but also a mutual solute region is formed between DSA‐CS and EP matrix. Corn stalks esterified by DSA were used as reinforcement filler for epoxy resin. The cellulose in CS was mainly esterified. The tensile and impact strength of DSA‐CS 15/EP reached a maximum value. A mutual solute region is formed between filler and matrix. [ABSTRACT FROM AUTHOR]

The over usage of natural sand and cement has negative social and ecological effects. To address this, by-products of industrial wastes known as pozzolanic materials, including as fly ash, GGBFS, silica fume, and metakaolin, can be utilised with the manufactured sand in place of the natural fine aggregate and cement. As a result, the current research project discussed in this article examines the viability of replacing cement in concrete with pozzolana and crushed sand. Thus, this will address two issues at once: the large-scale use of pozzolanic materials and the preservation of natural sand quarries. The main objective of this experimental investigation is to find out the impact and durability properties of concrete produced by replacing natural sand by manufactured sand in varying percentages like 0, 10, 20, 30, 40, 50, 60 70, 80, 90, 100, and 20% cement replacing with pozzolanic materials. Cylindrical disc 150 mm diameter and 65 mm thick was tested for impact strength and chloride permeability 50 mm thick and 100 mm diameter samples were cast. The 28-day impact strength and chloride permeability of concrete mixed by partially substituting cement with pozzolan and partially substituting natural fine aggregate with artificial sand were tested. For the various concrete mix proportions, the findings for impact strength and chloride permeability were examined and contrasted with standard concrete. The results of this study show that substituting 20% of the cement with silica fume and 60% of the natural fine aggregate with M-sand results in concrete that has a maximum impact strength and a minimum chloride permeability. An ANN Model was developed using the experimental values. For design of model 400 result values where used, 20% results used for testing purpose and 80% results used for ANN model training. Calculated using the product of 25 input data. The ANN model's results offer a precise elastic prediction of the impact strength and chloride iron pass ability of concrete mixed with substituting industrial cementitious waste for cement and artificial sand with naturally occurring fine aggregate. The findings of this study help to reduce the extraction of non-renewable natural recourses and the environmental impact of industrial waste by preparing more sustainable concrete. [ABSTRACT FROM AUTHOR]

Highlights Despite the wide use of three‐dimensional (3D) woven composites in different applications, their production is often costly. This study explores cost‐effective 3D orthogonal woven polymer composites to enhance mechanical performance. Four 3D composite variants, each incorporating different volumes of z‐binders (copper wires or glass fibers), were compared to a 2D woven composite. All composites were produced using a simple, economical hand lay‐up method. Wear resistance, in‐plane shear strength, and impact strength were assessed. Results indicated that all 3D composites surpassed the 2D composite in impact strength, especially those reinforced with glass fiber z‐binders. The single glass fiber z‐binder composite exhibited the highest impact strength increase (20.6%). Most 3D composites showed slightly reduced in‐plane shear strength compared to the 2D composite, with the smallest decrease (1.68%) observed in specimens with a small copper z‐binder. Notably, all 3D composites demonstrated superior wear resistance to 2D counterparts under various loads. Glass fiber z‐binder reinforcements outperformed copper z‐binders, with double fiber z‐binders yielding the maximum wear resistance enhancement. These findings underscore the potential of 3D woven composites for applications demanding high impact and wear resistance, such as automotive, structural components, and sports equipment. 3D woven composites are widely used in various engineering applications. Limited studies explore the in‐plane shear and wear behavior of 3D composites. Copper and glass fiber z‐binders were used in manufacturing 3D woven composites. The used hand lay‐up method reduces manufacturing costs. 3D woven composites improve impact and wear resistance compared to 2D ones. [ABSTRACT FROM AUTHOR]

Highlights Fiberglass‐reinforced composites are extensively utilized in a diverse range of fields. Nonetheless, relying on the high shear forces generated during twin screw extruder processing to enhance the dispersion and distribution of glass fibers (GFs) can result in GF breakage and the degradation of the molecular chains of polyamide (PA). Consequently, this leads to a diminished performance of the composite material. In this study, high‐performance PA6/GF composites were effectively fabricated through the utilization of a dual‐speed non‐twin screw extruder operating within a chaotic field. Furthermore, optimization was achieved by substituting the kneading block (KB) with a perturbation ring element (PRE). In this paper, a comparative analysis was conducted between the flow fields and experimental results obtained from varying thread arrangements. The result indicates that, in comparison to KB with discontinuous structures and sudden geometric shapes, PRE elements possessing open structure in both the transverse and longitudinal directions effectively mitigated the shear effect and residence time during processing. This led to the significant enhancement of the residual length of the GF, molecular weight of PA6, heat distortion resistance and thermal stability of the composites. Additionally, enhanced performance was observed in PA6/GF composites prepared using the PRE configuration. Specifically, PA6/GF composites prepared by PRE S3 configuration showed outstanding impact strength of 13.3 kJ/m2 and a tensile strength of 151.6 MPa, representing respective increases of 15.7% and 6.9% compared with those prepared using the twin screw extruder (TSE). This work introduced an innovative device and molding technique for the production of high‐performance fiber‐reinforced polymer composites. High‐performance PA/GF was successfully manufactured by non‐twin screw extruder. The modified non‐twin screw leaded to better dispersion and distribution of GF. The damage of fiberglass and the degradation of PA were significantly reduced. The mechanical properties were significantly improved without using additives. The heat distortion resistance and thermal stability of PA/GF were improved. [ABSTRACT FROM AUTHOR]

Highlights Thermoplastic polyacrylate resin, which can be polymerized in situ, has a broad application prospect. Addressing the issue of poor toughness of polyacrylate resin, a toughening method involving in situ polymerization of polyacrylate resin for liquid composite molding was presented in this paper. KH570‐modified silica nanoparticles were used as reinforcement. The study focused on the surface modification's impact on the dispersion stability of the nanoparticle suspension, the effect of nanoparticles on the reaction, and the mechanical properties of the resin. The results showed that the contact angle between modified‐silica and acrylate resin decreased from 79.3° to 9.96°, and the stability of the suspension was increased by 34.8%. With the increase of silica nanoparticles, the reaction speed of the resin initially decreased and then increased. This was due to the influence of KH570 on the surface of the nanoparticles and the changes in resin viscosity caused by the nanoparticles. The mechanical properties of polymerization products first increased and then decreased. When nanoparticles mass ratio of nanoparticle to resin was 5:100, the elongation at break was increased by 94.9%, the impact strength was increased by 287%. This paper provided some ideas for high‐performance industrial application of high‐performance in situ polymerization of polyacrylate resin. The thermoplastic polyacrylate resin that can be formed by liquid composite molding. A method for improving the toughness of resin used in liquid composite molding. Nanosilica modified with KH570 interferes with the reaction of acrylate resin. The nanosilica changes the crack propagation path. [ABSTRACT FROM AUTHOR]

Experiments have been performed in air and cooling-assisted condition with three tool pin profiles i.e. square, triangular and threaded cylinder. In this study, an effort has been made to comprehend how the mechanical characteristics, micro-hardness, and microstructure of friction stir welded AA6063-T6 joints are affected by in-process cooling, tool profiles, tool dimensions, and process parameters. For friction stir welding with cooling assistance, process parameters were optimised. For higher tensile and impact strength, a square tool profile with a shoulder to pin diameter ratio of 3:1 is found to be the most effective. The most important welding parameter was found to be rotations per minute (rpm). Microstructural analysis reveals finer grain size and a significant increase in microhardness in the weld nugget zone with cooling assisted FSW. [ABSTRACT FROM AUTHOR]